Field of the Invention
The present invention relates to an organic light emitting device, and more particularly, to an organic light emitting device and an organic light emitting display device using the same, for changing a structure of an emissive layer to enhance viewing angle characteristics and a lifespan.
Discussion of the Related Art
Recently, as the information age has fully arrived, the field of displays that visually display electrically conveyed information signals has developed rapidly. In response to this, various kinds of flat panel display devices having excellent characteristics, such as a small thickness, a low weight, and low power consumption, have been developed and have rapidly replaced existing cathode ray tubes (CRTs).
Representative examples of such flat panel display devices may include a liquid crystal display (LCD) device, a plasma display panel (PDP) device, a field emission display (FED) device, and an organic light-emitting display (OLED) device.
Among these, the organic light-emitting display device is considered to have a competitive application because it does not require a separate light source and enables realization of a compact device design and vivid color display.
The organic light-emitting display device includes organic light-emitting elements, which are independently driven on a per-sub-pixel basis. Such an organic light-emitting element includes an anode, a cathode, and a plurality of organic layers between the anode and the cathode.
The organic layers include a hole injection layer, a hole transport layer, an organic light-emitting layer, and an electron transport layer, which are sequentially disposed from the anode. Among these, the organic light-emitting layer substantially functions to emit light as the energy of excitons, produced via the combination of holes and electrons, falls down to the ground state. The other layers function to assist in the transport of holes or electrons to the organic light-emitting layer.
An organic emissive layer includes hosts and dopants and emits light in a corresponding wavelength in which dopants operate. However, there is a problem in that a generally known organic light emitting device differently recognizes color depending on an angle at which a viewer sees and a lifespan of a material with excellent viewing angle characteristics is degraded and, accordingly, research has been conducted into an organic light emitting device with the enhanced viewing angle characteristics and lifespan.